ios - 如何在将当前 View 缩放到 0.5% 之前弹出父 View Controller 以在后台绘制

Question

我正在尝试使用变换比例动画 popViewcontroller

根据这段代码，当它开始转换时，它会呈现黑屏而不是父 View

如何解决这个问题？

[UIView animateWithDuration:0.5f
                          delay:0.0f
                        options:UIViewAnimationCurveEaseInOut
                     animations:^{
                         self.view.alpha = 1.0f;
                         self.view.transform = CGAffineTransformMakeScale(0.5f, 0.5f); 
                     } completion:^(BOOL finished) {
                        [[self navigationController] popViewControllerAnimated:NO]; 
                     }];

Answer 1

这是预期的行为，因为在调用 popViewControllerAnimated: 方法之前，之前 Controller 的 View 不在 View 层次结构中，并且您在动画完成后调用它。

我不认为将 subview 直接添加到导航 Controller 的 View 是个好主意，但以下代码应该适合您。

UINavigationController* navigationController;
CGRect frame;

//keep a reference to the navigation controller as
//[self navigationController] won't work after pop is called
navigationController = [self navigationController];

//remember the frame of the view relative to navigation controller's view
frame = [navigationController.view convertRect:self.view.frame fromView:self.view.superview];

//pop this controller, this will add the view of the
//previous controller into the view hierarchy
[navigationController popViewControllerAnimated:NO]; 

self.view.frame = frame;
//add this view on top of the previous one 
[navigationController.view addSubview:self.view];

[UIView animateWithDuration:0.5f
                      delay:0.0f
                    options:0
                 animations:^{
                     self.view.alpha = 0.0f;
                     self.view.transform = CGAffineTransformMakeScale(0.5f, 0.5f); 
                 } completion:^(BOOL finished) {
                     [self.view removeFromSuperview];
                 }];

顺便说一句，UIViewAnimationCurveEaseInOut 不是选项参数的正确常量。对于此方法，您应该使用以 UIViewAnimationOption 开头的常量。